Method of forming plow disks



Aug. 4, 1942. R. c. INGERSOLL I METHOD OF FORMING PLOW DISKS 2 Sheets-Sheet 1 Filed Oct. 25, 1939 f? F y C ifweivmsolz I Aug. 4, 1942. R. c. INGERSOLL METHOD OF FORMING PLOW DISKS Filed Oct. 25, 1959 2 Sheets-Sheet 2 .[712/6? 7 2.507 figy C figgensall 1?" Patented Aug. 4, 1942 METHOD OF FORMING PLOW DISKS Roy 0. Ingersoll, Winnetka, 11L, assignor to Borg- Warner Corporation, Chicago, 111., a corporation of Illinois Application October 25, 1939, Serial No. 301,099

10 Claims.

This invention relates to disks, and particularly to a method of forming plow, harrow and other tapered agricultural disks. This application is a continuation in part of my co-pending application Serial No. 159,089, filed August 14, 1937.

The usual plow disk is comprised of a steel disk which has been cambered or dished to a substantially frusto-spheroidal shape. The edge of the disk is beveled to present a sharp cutting edge to the soil, and the central region is provided with a suitable apertur for mounting the disk upon the implement with which itis to be used.

The practice generally employed for forming plow disks is to start with a flat bank, heat the blank to forging temperature, roll a bevel on the edge region, and then drop forge the disk between suitable dies to a cambered shape. In the forging operation, however, the movement of the metal is uncontrolled. Obviously, as the contour of the disk is changed from planar to spherical, the metal must be upset in order to allow for the decreased diameter which results. Upsetting, however, requires aconsiderable amount of force in the plane of the metal and in view of the thinness of the metal, together with its softness at forging temperatures, the metal tends to buckle and form wrinkles rather than upset.

It has been the practice to camber the disk by means of several light blows with the drop hammer, rather than with a single heavy blow, to reduce the amount of buckling, and to strike the disk sharply after it has been substantially completely cambered in order to remove wrinkles. This practice has never been completely satisfactory, partly because of the increased time required to form the camber, and partly because the wrinkles were not completely eradicated by the final sharp blows. To function properly as a plow the disk must be perfectly smooth, otherwise it will not scour properly. The resulting disk, therefore, had to be ground to remove the last vestiges of the wrinkles.

The object of this invention is to provide an improved method for forming cambered disks in I the exercise of which the metal of the disk is become apparent from the following description when taken together with the accompanying drawings forming part thereof. in which:

Fig. 1 is a beveled flat disk from which the plow disk is made; y

t Fig. 2 is an elevation in section of the drawing dies used in the method of forming the camber in the disk of Fig. 1;

Fig. 3 is an enlarged fragment of the dies of Fig. 2 showing the initial stage of the operation of the dies;

Fig. 4 is 'an enlarged fragment in section of the dies showing an intermediate stage; and Fig. 5 is an enlarged fragment in section showing the final stage of the operation of the die.

In its preferred form, this invention comprises the steps of heating a steel disk to forging temperature, rolling a bevel on one surface of the disk, gripping the disk over the beveled region thereof, simultaneously drawing the disk overa convex die, and, finally, compressing the entire disk between the dies. I am aware that it is old to form sheet metal to various shapes by means of a, drawing operation. The ordinarydrawing operation, however, if applied to a plow disk would not be satisfactory for the reason that it would result in a disk which is deeply scarred with die marks. These die marks could, of course, be

eliminated by starting with a very large disk and then trimming of! the portion which is marked. Such a procedure, however, would be too costly to be commercially feasible. The problem has been to camber a disk by means of dies in a manner which would not require any subsequent trimming operation, which would not result inxdie marks and which nevertheless, would eliminate wrinkles.

l I havediscovered that a satisfactory cambered plow disk may be obtained by gripping the beveled portion of the disk with a draw ring, the operative surface of which is an extension of the surface of the central portion of the die, and by permitting the upper die to slide over the beveled portion as the draw ring moves with the die. By

so gripping the disk, the material willbend at the outer ends rather than take an impression I from either die, and, in addition, will besliding over the surfaces of the disk continuously, thereby preventing a concentration of force at any one point. I 7

Referring now to the drawings for a detailed description of the invention, the flat blank from which the plow disk is formed is shown in Fig. 1.

i The blank I0 is heated to forging temperature and then is placed between suitable rolls to form a bevel ii on one surface-thereof.

The heated and beveled disk ID has an aperture l2 formed therein, preferably prior to the rolling operation and simultaneously with the blanking operation. The disk is placed upon a die l3 having a centering pin l4 which passes through aperture l2. Disk i rests upon a hardened insert l5 and also upon the upper corner l6 of draw ring l1. Insert l5 has formed therein a shoulder l8 which connects a flat surface l9 at the central portion with a convex surface 20 in the edge region of the insert.

The upper surface 2| of die I3 is an extension of surface 20. The upper surface 22 of draw ring I! is an extension of surface 2| of die I3 so that when draw ring 11 is at the bottom of its stroke, surfaces 20, 2| and 22 form continuations of one another.

The draw ring ll' rests upon pins 23, which are spaced circumferentially about die l3 and are urged upwardly by means of springs 24, compressed air, or the like.

Upper die 25 has a central insert 26 which cooperates with insert l5 to form the central region of disk l0. Upper die 25 extends over both lower die l3 and draw ring l1. Its concave surface 21. is adapted to form the upper surface of disk Id.

Referring now to Figs. 3, 4 and 5, the method of cambering disk It] is as follows;

It will be noted in Fig. 3 that corner l6 of draw ring I! contacts the lower surface of disk I0 just below the point where bevel H joins the re-.

mainder of the upper surface of disk Hi. It will also be noted that the corner 28 formed by the concave surface 21 of upper die 25 and the unformed fiat surface 29 contacts disk ID on the beveled portion thereof and a slight distance inward from the edge of the disk. The first step in the cambering operation, therefore, is to grip disk Ill between draw'ring l1 and upper die 28 at the beveled region of the disc. It will be noted that the gripping action is not a compressing action, but rather a bending action.

As the upper die descends, it soon exerts enough force to overcome the upward thrust of springs 24 upon pins 23 and draw ring I! then commences to move downward with the upper die. Before it begins its descent, however, disk III will be bent over corner 16 and as draw ring I! descends, the metal of disk ID will be drawn downward and radially inward over corner l6 as shown in Fig. 4. Simultaneously corner 28 of upper die 25 slides radially outwardly along bevel ll, contacting progressively thinner and consequently more easily bent sections of the disk as it slides. This results in a continuous flexure over corner l6, which is necessary to provide the gripping action for drawing the disk downwardly and at the same time exerting enough tension on the metal as it upsets to prevent the formation of wrinkles.

Near the bottom of the stroke, where the bent surface of the disk is substantially parallel with the surface of the lower die and draw ring, the gripping action is no longer confined to corners l6 and 28, but takes place along the upper surface of draw ring I! and the lower edge region of surface 21 of upper die 29, which region has been shaped to accommodate the bevel. From 'this point on, the shoulder 18 in insert l5 commences to form disk l0, and in so doing, still further adds to the forces tending to slide disk I0 over the draw ring and the surface of upper die 25. At the bottom of the stroke, draw ring I! rests upon base plate 30 of the press and becomes a part of disk.

lower die I3. The disk in then compressed between the dies to give it its final form. It will be noted that at the bottom of the stroke edge 28 of upper die 25 coincides with the edge of disk l0, and therefore, will form no marks thereon.

The foregoing method results in a plow disk which is perfectly cambered, and which is neither wrinkled nor deeply marked by dies. The disk requires no subsequent trimming operation, since it was formed in its entirety between the dies. The reason for the success of this method where the ordinary draw ring method fails, is in the location of the draw ring with respect to the disk. Thus, if the draw ring and lower die were parted at a distance radially inward from the position shown, a satisfactory result could not be obtained. The portion between the draw ring and the center of the disk might be properly formed, but the force required to do so would be such that the draw ring would bite into the under surface of the disk. On the other hand, if draw ring I! and lower die l3 were parted at a distance radially outward from the one shown, the force upon the bevel would be too great for the thickness of metal thereat for one thing, and in addition, the upper die would slide off the bevel and thereby destroy the gripping action which is so necessary for the drawing operation.

Draw ring I! also acts as an ejector for the disk and for this reason a portion of the disk must remain over draw ring I! at the end of the stroke.

It is understood that the foregoing description is merely illustrative of the preferred embodiment of my method, and that the scope of this invention, therefore, is not to be limited thereto, but is to be determined by the appended claims.

I claim:

1. The steps in the method of making agricultural implement disks which comprise forming a bevel on one surface of a disk, cambering the disk by drawing the disk over a convex die, and simultaneously gripping opposite sides of the disk at the beveled region with line contact to prevent the formation of wrinkles in the disk.

2. The steps in the method of making plow disks which comprise forming a bevel on one surface of a flat disk, cambering the disk by drawing the disk over a convex die, and gripping opposite sides of the disk with line contact during the drawing operation to prevent the formation of wrinkles in the disk, said gripping action being limited to substantially the beveled region of the 3. The steps in the method of making plow disks which comprise forming a bevel on one surface of a flat disk, cambering the disk by drawing the disk over a convex die, and gripping opposite sides of the disk with line contact over the beveled region during the drawing operation, said gripping action being just suflicient to prevent the formation of wrinkles in the disk but being insufficient to form an appreciable die mark in the disk.

4. The steps in the method of forming plow disks which comprise heating a flat disk to forging temperature, forming a bevel on one surface, cambering the disk by drawing said disk while hot over a convex die, gripping opposite sides of the beveled region with line contact during the drawing operation to prevent the formation of wrinkles in the disk, and compressing the beveled region between dies to shape said beveled region.

5. The steps in the method of forming plow disks as described in claim 4, said gripping action being sufficient to prevent the formation of wrinkles, but being insufficient to cause appreciable marks in the disk.

6. The steps in the method of making plow disks which comprise forming a bevel on one surface of a disk, cambering the disk by drawing the disk over a convex die, gripping opposite sides of the beveled region with line contact during the drawing operation with a force suflicient to prevent the formation of wrinkles in the region between the inner edge of the bevel and the center but insufficient to mark the disk, and compressing the beveled region between dies to shape said region.

'7. The steps in the method of making plow disks which comprise heating a disk to forging temperature, rolling a bevel on one surface of the disk, cambering the disk by drawing the disk over a convex die, gripping opposite sides of the beveled region with line contact during the drawing operation with a force suflicient to prevent the formation of wrinkles in the region between the inner edge of the bevel and the center, but insufiicient to indent the surface of the disk, and compressing the entire disk including the beveled region, between dies to shape the disk.

8. The steps in the method of making plow disks which comprise forming a bevel on one surface of a disk, cambering the disk by drawing the disk over a convex die, and simultaneously gripping the disk at the beveled region with a bending action which imposes a sufiicient radial force on the disk to prevent the formation of wrinkles therein, but which is insufficient to form appreciable die-marks.

9. The steps intthe method of making plow disks which comprise forming a bevel on one surface of a disk, cambering the disk by drawing the disk over a convex die, and simultaneously progressively bending the beveled region radially outward over a draw ring, the bending action being insufficient to form appreciable die-marks, but being sufficient to prevent the formation of wrinkles in the disk.

10. The steps in the method of making plow disks in accordance with claim 9, and finally compressing the entire disk between dies to form a shoulder in the disk, said shoulder-forming step causing a radially inward movement of the metal over the dies to prevent a concentration of force over a small area whereby to prevent the formation of die-marks in the final step of the method.

ROY C. INGERSOLL. 

